body { font-family: sans-serif; } h2:first-child { margin-top: 0; } h2 { margin-top: 3rem; margin-bottom: 1rem; } h3 { margin-top: 2rem; margin-bottom: 1rem; } code { color: navy; background-color: #eee; border-radius: .25rem; padding: .125rem .25rem; } .btn-animated { animation: 1s linear infinite btn-animated; } @keyframes btn-animated { 0% { box-shadow: none; } 50% { box-shadow: 0 .5rem 1rem rgba(0, 0, 0, .5); } }